PHILADELPHIA (AP) -- Police say an apparent case of road rage ended in a car chase that followed a small crash in West Philadelphia resulted in a second crash that injured an elderly couple.

Officials said a man driving one car allegedly fled a 4 p.m. Tuesday crash in the Wynnewood section of West Philadelphia with another car, which pursued the first vehicle.

Police said the first car eventually slammed into a vehicle carrying a 90-year-old man and an 82-year-old woman in the Wynnefield section of the city.

The two victims were taken to Hahnemann Hospital for treatment.

Witnesses reported that the two drivers then got into an argument, and one threatened the other with a knife.

Both were taken into custody by police, but no charges were immediately filed.

The final tally on the damage? Ttwo elderly innocent bystanders injured, six total vehicles damaged and two suspects under arrest.

Philadelphia Police said that it all began with a minor fender bender as the driver of a blue Buick Park Avenue hit a white Nissan Maxima at 54th and City Avenue in the Wynnefield section of the city around 3:45 this afternoon. Investigators say the driver of the Buick fled the scene as the enraged driver of the Nissan gave chase.

About a mile away, on the 2200 block of Bryn Mawr Avenue, the 25-year-old driver of the Buick lost control and rammed head on into an elderly couple's gold Honda Accord. The unidentified 90-year-old driver of the Honda and his 82-year-old wife were taken to the hospital with serious injuries -- the man remained in critical condition with broken ribs and a chest injury and the woman was in stable condition.

The 29-year-old driver of the Nissan allegedly then got out of his car and chased the other driver with a knife. The driver of the Buick ran into a nearby Produce Junction, police said.

Shoppers ran out of the store and called 9-1-1. Within minutes both men were under arrest.

Neither alleged road rage driver was seriously hurt. Police say the driver of the Buick will be charged with leaving the scene of a crash and the head-on wreck while the other driver will be charged with aggravated assault, terroristic threats and related charges.